Eric Sloof

Veeam has released The First Annual Report on VMware Data Protection. They hired an independent research firm, to survey 500 enterprises CIOs. Vanson Bourne, an independent market research organization, conducted an online survey in August 2010 of 500 CIOs from organizations across the United States, United Kingdom, Germany, and France that employ more than 1,000 people.

FirstAnnualReportonVMwareDataProtection-SurveyResults.pdf

In this video I’ll show you how to enable the Vmkernel System Info Shell (vsish) on an ESX host. The vsish is normally only available on an ESXi host but in this video you will see and learn that it’s also working on ESX. With vsish you can examine the VSI (VMkernel System Information) which can be useful when troubleshooting or adjusting advanced setting that are not exposed in the vSphere Client. My virtualization friend William Lam over at virtuallyGhetto has retreived a list with all the 250 hidden advanced settings. He created a great article about “What is VMware vsish?”. I don’t have to remind you that vsish is able to damage your system so use it with caution. You can also watch the HD version of this video on <YouTube> and <ScreenCast>.

Here's some additional information I've received from Krishna Raj Raja regarding vsish:

VSISH - VSI (Vmkernel Sys Info) Shell - is the interface to access/modify live vmkernel data structures/variables.

Nearly all the configurations under the /config node in vsish are modifiable through vCenter - Software settings -> Advanced settings.

Since vsish binary access vmkernel memory data structures it is build version dependent, one cannot use a vsish binary from one ESX build onto another ESX host with a different build.

vsi_traverse binary - dumps the VSI information into binary format - vm-support script command uses this to capture the system state. When collecting performance snapshot, vm-support script captures vsi snapshot every few secs. esxtop when run in replay mode will fetch data from the VSI snapshots instead of the data from the live system. vsish -c option allow vsish to fetch information from the vsi snapshot (generated by vsi_traverse) instead of using the live system.

In this article I want to set the record straight regarding last week’s article about New in esxtop RESV/s (SCSI reservations per second). During VMware Communities Roundtable Podcast number 118 with Krishna Raj Raja. I have learned that I didn’t measure the right metric with the correct method so now I’ve used the right method and metric -> CONS/s. I hope you will enjoy it. You can also watch the HD version of this video on <YouTube> and <ScreenCast>.

I’ve received an email from Krishna Raj Raja with some additional details about SCSI RESV/s and CONS/s counters.

- A nonzero value for RESV/s counter indicates that the host is doing some metadata operation on the VMFS volume (like creating a file, allocating disk space, file rename, permission change, timestamp update etc) - this by itself does not cause any performance problem.

- SCSI reservation conflict counter - CONS/s will become non-zero  when a host tries to do any I/O on a LUN which has a SCSI reservation in progress.

- SCSI reservation is held for a very short period (few hundred microseconds) so the chances of a getting a conflict is very less on a small cluster. However as the number of hosts that shares the LUN increases conflicts could arise more frequently.

- SCSI reserve/release commands have higher priority and they are placed ahead in the host's SCSI I/O queue for immediate dispatch.

- When SCSI reservation is held on a LUN, I/O issued by a VM going to that LUN will fail with the BUSY status within the guest, and the guest will have to retry the I/O. This could result in an end to end increase in I/O latency for that particular I/O.

- The new vSphere 4.1 feature - VAAI - has support for ATS (Atomic test and set) functionality which is a replacement for SCSI reservation and it provides much faster/granular locking mechanism. Performance impact is very little if ATS is used instead of SCSI reserve/release mechanism.

This document describes the technical aspects of NetApp support and integration with VMware® vStorage APIs for Array Integration (VAAI), as well as how to deploy and use this technology. VAAI is a set of application programming interfaces (APIs) and SCSI commands that offload certain I/O-intensive tasks to NetApp® storage systems. By integrating with vStorage APIs, NetApp enables advanced storage capabilities to be accessed and executed from familiar VMware interfaces, improving manageability, performance, data mobility, and data protection.

http://media.netapp.com/documents/tr-3886.pdf

VMware has released the beta of a new training course called VMware vCloud: Architecting the VMware Cloud. This course is designed to guide students through the decision points and policy choices available for designing and implementing a VMware vCloud environment. Students will learn to appreciate the effects of design choices in VMware vSphere 4, VMware vCloud Director, VMware vCenter™ Chargeback, and the VMware vShield Edge functionality that is included with vCloud Director. The course culminates in a comprehensive workshop about VMware cloud design.

PortBox PL: Serial to Ethernet device server

RS-232/485 serial line - Ethernet converter on TCP/IP and UDP/IP protocol. Built-in virtual serial port support, the remote port can be mapped as for example COM1 in VM using the HW VSP utility. 9-bit support extension, wide support of RS-485 question-answer communication support.A typical application is access a remote technology controlled over RS-232 of RS-485, or serial port prolonging via the Ethernet network.

http://www.hw-group.com/products/converter/index_en.html

Moxa NPort 5100A

The NPort 5100A device servers are designed to make serial devices network-ready in an instant and give your VM direct access to serial devices. The NPort 5100A device servers are ultra lean, ruggedized, and user friendly, making simple and reliable serial to Ethernet solutions possible.

http://www.moxa.com/product/NPort_5100A.htm